The overall objective of the Animal Models Core is to provide expertise to members of the CURE: Digestive Diseases Research Core Center (CURE: DDRCC) for in vivo characterization of normal and pathophysiological mechanisms of hormonal and neural regulation of gastrointestinal (GI) function and brain-gut interactions in rodents. The specific objectives are to provide CURE: DDRCC investigators access to: (1) in vivo experimental models to assess gastric and intestinal function in rats and mice; (2) specialized facilities and equipment to measure GI secretions, motor function, blood flow, resistance of the mucosa to injury and functional mapping of neuronal activity at the cellular level; (3) methods for in vivo administration of peptides, neurotransmitters, and drugs, sampling blood and body fluids, and tissue collection; (4) methods to assess afferent and efferent arms of the neural pathways involved in brain-gut interactions; (5) expertise in protocol design, data analysis and program development for analysis of electrophysiological traces; and (6) transgenic animals with specific gene mutations through interaction with transgenic Cores within UCLA.